Black eyes and black blood
by hunterintrenchcoat
Summary: Demon!Dean meets Leviathan!Castiel. (Rated M for heavy violent smut, WARNINGS inside)


_WARNINGS: this is __**heavy**__ stuff, it's a very very violent smut fic: it contains violence, injuries, knifeplay, blood, kind of dub-con/non-con (I still can't tell but I'm warning you anyway), threats, very rough sex, dirty talk, insulting and swearing. Please, think twice before reading and avoid this if you're too sensitive._

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"Oh, this is going to be so much fun."

Black veins run up his neck as Castiel grabs the demon by the collar and slams him hard against the wall. Dean's eyes immediately turn black and he growls threateningly as the leviathan slowly approaches and tilts his head to the side, grinning and studying the man in front of him. He pins Dean to the wall and smashes their lips together, shoving his tongue inside his mouth and swirling it around before biting down on his bottom lip hard enough to draw blood. He sucks on it and moans, tasting the demon and grounding their hips together roughly and painfully. Dean runs a hand through his hair and then yanks it back, forcing his head back and biting at the black veins that keep moving and pulsing, breaking the skin and letting blood drip down the collar of his white shirt.

"C'mon, you hellspawn, is this everything you've got?"

The leviathan sneers as Dean grabs him by the trench coat and tries to switch position uselessly: he's far too strong for these useless fuckers that demons are. He tears Dean's t-shirt off without bothering to take his leather jacket off first and ranks his nails down his chest, leaving five bloody-red stripes that sting on Dean's skin. The demon barely growls as he's forced to his knees but he doesn't waste time: he yanks at Castiel's belt and pulls it off before breaking the zipper and ripping the upper part of the pants open. A hand immediately wraps around his neck and tighten his grip, breaking the bone in one single fluid motion and Dean groans louder this time: it hurt like hell, but it's not like the damage can really kill him.

"Yeah, that's not going to hurt me that much. Sorry to disappoint you, dickhead."

The demon smirks as he rotates his head to readjust the broken bone and shoving a hand inside his leather jacket, pulling out a knife and digging it into the flesh of the leviathan's thigh, black blood smearing the blade and running down the trousers that are slowly sinking to his ankles. Castiel merely lowers his head to glance at the silver knife that disappears inside his flesh and then kicks Dean in the face with his knee before pulling out the demon knife from his trench coat and cutting his cheek. The wound lights up with demonic fire and Dean immediately pushes at the leviathan's waist with such furious force he finally manages to break his balance and shove him away.

"Now you're going to pay, motherfucker."

"Oh, Dean, I don't think so. What do you low-life fuckers think you can do when you can't even use a knife properly?"

The demon raises his hand to use his powers but nothing happens. When he tries again, Castiel laughs out loud in pure amusement, an evil laughter building up from his throat and echoing throughout the room. He pushes Dean against the wall again and gets a firm grip on his hair, shoving his crotch against his face and the demon quickly gets the message. He pulls the leviathan's hard cock out of his boxers and opens his mouth, but before he can do anything, the demon blade is on his throat and he stills. That thing can really kill him if he's not careful.

"Don't you dare do anything stupid or I'll cut your fucking throat."

Dean chuckles before Castiel quickly shoves his whole length down his throat and groans loudly as the demon swallows him down without mercy and begins to bob his head back and forth, taking it all until the tip of his nose touches his groin. He dares to rake his teeth on his sensitive skin and he expect the blade to cut his throat, but the leviathan just moans loudly and thrust harder, knocking Dean's head against the wall and pinning him there as he continues to push into his mouth hard enough to break his lips. The demon groans around him and closes his eyes, palming himself through his own jeans as blood and spit drip down his chin and smear the floor.

"You really like it rough, don't you? You black-eyed whore."

Castiel pulls away and uses his grip on Dean's hair to throw him face on the ground, before pressing a knee between his shoulder blades and pinning him there. He uses the demon knife to tear his jeans open and grabs him by the hair, forcing his whole body backwards, arching his spine in a painful angle until his lips are on the demon's ear. He licks at the earlobe and shoves his tongue inside the shell as he rubs his dick against his ass still half-covered by the ruined fabric of the jeans. He runs the tip of the demon blade up his chest, tracing his ribs and his nipples with it, and Dean moans loudly, pushing his hips back against Castiel's groin.

"What are you waiting for, dickhead?"

"Shut up, slut."

The leviathan sharply pulls Dean's underwear down and takes a firm grip on his cock, stroking it hard and rough, as the other hand presses the blade on his chest, cutting open long wounds that burn and light up as soon as the silver tip makes contact with the skin. The pleasure mixed with the intense pain soon has Dean moaning and trembling like a whore under Castiel's violent touch and as soon as he's reaching the edge, the leviathan pulls away to get completely rid of the demon's pants. He immediately pushes inside of him until he's buried to the hilt and Dean just moans and pushes back, meeting Castiel's immediate relentless thrusts.

"Yes, yes, fuck!"

"Look at you, my good little whore."

Castiel pounds inside him mercilessly without pausing, pulling sharply at Dean's short hair and biting down hard on his neck, sucking his demonic blood greedily and stroking his balls with the tip of the demon knife without injuring him. Dean shouts and begs for more, heat quickly coiling up his groin as the leviathan hit his prostrate over and over, abusing it brutally as he keeps thrusting so hard he can almost hear his tailbone cracking up. Castiel himself is very close to coming already since Dean's shouting and clenching around him is driving him completely mad. He speaks in his ear through gritted teeth, threatening to torture him until he'll beg to return to his Hell to have some break and Dean all but laughs because this is fucking Heaven compared to that shitty hole that Hell is. Not even Purgatory feels this good. Castiel knows perfectly.

"Harder, you bastard! Or are you too scared of breaking me? C'mon!"

The demon reaches back to grab the leviathan's ass and push him closer and a snapping noise fills the room as Castiel thrusts even harder to comply his request and breaks his cracked tailbone. Dean completely ignores it as he ranks his nails hard on Castiel's cheeks, drawing black blood that trickles down his thighs, and the leviathan groans loudly, smacking the demon's forehead right on the floor and pinning him there with his whole weight. His thrusts are far above the brutal and cruel now and both his and Dean's blood is smearing the floor but neither of them cares about it. Sure, Dean's the only one who can technically die here, but not until Castiel decides to stab him with the goddamned demon knife and that's not even close to what the leviathan has in his mind at the moment.

"You like it, don't you? You like having me fuck you so hard your bones break, huh?"

Castiel roughly palms his balls and squeezes, driving the blade down his chest deep and hard, close to kill Dean instantly. The demon tenses up and shakes, coming all over the floor with a loud 'oh fuck' as the leviathan snaps his hips hard and fills him up with his own release without stopping the thrusting until he has completely ridden out his orgasm, not caring about Dean's over-sensitized prostrate that sends painful shock waves to his spent cock. Dean falls forward and rests on his back on the floor, trying to regain his strength quickly before Castiel does and get the chance to act first. His hopes die when the leviathan instantly straddles his hips and attempts to shove the demon blade down his throat, but he manages to block the attack and roll them over, trapping him below him.

"Don't tell me you really thought it would be this easy."

"I admit it, I did."

"Poor bastard."

Castiel laughs as he kicks Dean away from him and shoves the knife deep into his thigh in a quick motion, right where it would hurt like a bitch but not actually kill. The demon screams as his whole body flares with hellish light and black eyes glare fiercely at the leviathan who is standing up and and looking down at him. Castiel tilts his head to the side and darkly chuckles as he finally stops lighting up like a pathetic Christmas tree and sharply pulls out the knife from his flesh.

"Well, now that I think better about it...why should I kill a good fuck like you?"

"Keep dreaming."


End file.
